PreparedStatement & MySql not working ! Why ?!!?

Question

Hello everyone. One question for you : I try to have a SELECT on a table to get a column value. I've used for that a preparedstatement but id didn't worked, I mean it returned nothing. Then I've used a simple statement which worked correctly. My question is why prepared doesn't work while simple statement do ?! Other querys work fine, but this one doesn't. And I simply don't get it... I need this preparedstatement way because I use this query very often.
I use MySQL Connector/J latest version, Java 1.4. Here's the code for this situation:
This doesn't work:
String sql = "SELECT IDUSER FROM SUBSCRIBERS WHERE MSISDN = ? AND SUBSCRIBER_TYPE = 0 AND RIGHTS <> 1 LIMIT 1";
PreparedStatement pstm = null;
ResultSet rs = null;
pstm = serviceConnection.prepareStatement(sql);
pstm.setString(1, MSISDN);
rs = pstm.executeQuery();
//gets the iduser from the query
if (rs.next())
iduser = rs.getInt("IDUSER");
else
iduser = 0;
This works:
String sql = "SELECT IDUSER FROM SUBSCRIBERS WHERE MSISDN = "+MSISDN+" AND SUBSCRIBER_TYPE = 0 AND RIGHTS <> 1 LIMIT 1";
Statement stm = null;
ResultSet rs = null;
stm = serviceConnection.createStatement();
rs = stm.executeQuery(sql);
//gets the iduser from the query
if (rs.next())
iduser = rs.getInt("IDUSER");
else
iduser = 0;
Thank's in advance.

Answer 1

MSISDN is a String or is a number?
The non PreparedStatement code works if the sql has
quotes arrounf this field?
String sql = "SELECT IDUSER FROM SUBSCRIBERS WHERE
MSISDN =' "+MSISDN+"' AND SUBSCRIBER_TYPE = 0 AND
RIGHTS <> 1 LIMIT 1";
This is something simmilar to the use of
PreparedStatement.setString();
The setters of prepared statements are not a simple
substitution in the sql string. Your database probably
are thinking that there aren't any row with "not a
number" in the MSISDN column.The MSISDN is a String representation of a number. And it works with/without the ' around for statements. What's strange is that if I change the prepared statement to be like this:
String sql = "SELECT IDUSER FROM SUBSCRIBERS WHERE MSISDN = "+MSISDN+" AND SUBSCRIBER_TYPE = 0 AND RIGHTS <> 1 LIMIT 1",
and I don't use the setString() method it still doesn't work :((